diff --git a/src/client/linux/handler/exception_handler_unittest.cc b/src/client/linux/handler/exception_handler_unittest.cc
index 3040e0f..2a08060 100644
--- a/src/client/linux/handler/exception_handler_unittest.cc
+++ b/src/client/linux/handler/exception_handler_unittest.cc
@@ -421,6 +421,10 @@
 
   const pid_t child = fork();
   if (child == 0) {
+    // Custom signal handlers, which may have been installed by a test launcher,
+    // are undesirable in this child.
+    signal(SIGSEGV, SIG_DFL);
+
     CrashWithCallbacks(FilterCallbackReturnFalse, NULL, temp_dir.path());
   }
 
diff --git a/src/client/linux/minidump_writer/linux_ptrace_dumper_unittest.cc b/src/client/linux/minidump_writer/linux_ptrace_dumper_unittest.cc
index a4a0fd9..3060327 100644
--- a/src/client/linux/minidump_writer/linux_ptrace_dumper_unittest.cc
+++ b/src/client/linux/minidump_writer/linux_ptrace_dumper_unittest.cc
@@ -144,8 +144,8 @@
     if (child_pid_ == 0) {
       // child process
       RealTestBody();
-      exit(HasFatalFailure() ? kFatalFailure :
-           (HasNonfatalFailure() ? kNonFatalFailure : 0));
+      _exit(HasFatalFailure() ? kFatalFailure :
+            (HasNonfatalFailure() ? kNonFatalFailure : 0));
     }
 
     ASSERT_TRUE(child_pid_ > 0);
@@ -250,7 +250,7 @@
   helper_path_ = GetHelperBinary();
   if (helper_path_.empty()) {
     FAIL() << "Couldn't find helper binary";
-    exit(1);
+    _exit(1);
   }
 
   // mmap two segments out of the helper binary, one
diff --git a/src/common/linux/tests/crash_generator.cc b/src/common/linux/tests/crash_generator.cc
index dd68113..3631967 100644
--- a/src/common/linux/tests/crash_generator.cc
+++ b/src/common/linux/tests/crash_generator.cc
@@ -184,6 +184,12 @@
 
   pid_t pid = fork();
   if (pid == 0) {
+    // Custom signal handlers, which may have been installed by a test launcher,
+    // are undesirable in this child.
+    if (signal(crash_signal, SIG_DFL) == SIG_ERR) {
+      perror("CrashGenerator: signal");
+      exit(1);
+    }
     if (chdir(temp_dir_.path().c_str()) == -1) {
       perror("CrashGenerator: Failed to change directory");
       exit(1);